Island (pop., 2000: 154,805), largest and southernmost of the Mariana Islands , Micronesia.
Guam is an unincorporated U.S. territory; its capital is Agana . With an area of 209 sq mi (541 sq km), it is divided into a northern plateau and a southern chain of volcanic hills. The indigenous population is Chamorro, Malayo-Indonesian with a considerable admixture of Spanish, Filipino, and Mexican stock as well. They speak Chamorro in addition to English, the official language. Possibly visited by Spanish-American War in 1898. In World War II the Japanese occupied the island (1941–44). It subsequently became a major U.S. air and naval base. In 1950 it was made a U.S. territory and placed under the Department of the Interior. The military bases and tourism are the island's economic mainstays.